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Resistive loaded breathing has a functional impact on maximal voluntary contractions in humans
Duncan Turner1, Stephen Jackson
1Exercise Neuroscience Research Group, School of Applied Science, South Bank University, London SE1 0AA, UK. turnerdl@sbu.ac.uk
Abstract:
Resistive loaded breathing (RL) can modulate the electromyogram pattern during an isometric arm flexion or leg extension at 70-80% of voluntary maximal contraction (MVC). This study tested the hypothesis that an interaction between the respiratory muscle afferent activity during RL and the descending motor drive may also have a functional impact on voluntary maximal performance. Therefore, muscle contractions (100% of MVC) were performed with four muscles during phase specific expiratory (ERL) or inspiratory (IRL) resistive loading and force or the steadiness of the force produced were compared with non-RL controls. Both IRL and ERL reduced MVC in leg muscles, especially biceps femoris. IRL caused a reduction in steadiness in the same muscle. These results suggest a hitherto understated impact of RL on functional performance in leg muscles.
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